RU2419813C2 - Method and device for measuring distance - Google Patents

Abstract

FIELD: physics. ^ SUBSTANCE: proposed device comprises signal source to output signal with multiple frequency components in one definite bandwidth, transmission module to transmit signal in the form of wave oscillation, module to detect mixed wave Vc resulted from mixing transmitted travelling wave VT and reflected wave VRk consisting of travelling wave VT reflected from measurement object, module to analyse frequency component of detected mixed wave Vc, and module of distance computation designed to obtain distance spectrum, process analysed data and compute distance to measurement object. ^ EFFECT: simple design, possibility to measure short distances and reduced errors. ^ 22 cl, 24 dwg

Description

FIELD OF THE INVENTION

The present invention relates to a distance measuring device and a distance measuring method, and more particularly, to a distance measuring device and a distance measuring method that detects a mixed wave consisting of a traveling wave outputted from a signal source and a reflected wave received from a traveling wave, reflected from the measurement object, and measure the distance to the measurement object.

State of the art

As conventional distance measuring devices, it is known to use an electric wave, a pulsed radar, an FMCW radar (LFMS, continuous frequency modulated signal) and other radars.

A pulse radar transmits a pulse signal, measures the time during which this pulse signal is reflected by the measurement object, and determines the distance to the measurement object. In addition, the FMCW radar transmits a continuous signal with a frequency oscillation and measures the distance to the measurement object from the frequency difference between the transmitted signals and the reflected signals. In addition to this, there is a spread spectrum radar, a coded pulse radar, and others, but these radars measure the distance based on the propagation time of the signals to the measured object and vice versa, as in the case of a pulsed radar.

At the same time, the above-mentioned radars, in principle, measure the propagation time of signals to the measured object and vice versa and have the disadvantage that their resolution is several tens of meters, so it is difficult to measure at close distances within a few tens of meters. In addition, due to the fact that the FMCW radar measures the distance to the measurement object from the frequency difference between the transmitted signals and the reflected signals, it raises the problem of maintaining the linearity of the frequency change of the transmitted signals, as well as the problem of a “fake object” related with leakage of transmitted signals to the receiving side; it also requires (at a high level) to maintain the accuracy of the output signals to satisfy the linearity of the frequency change, it is required to use separate antennas for the receiving side and the transmitting side in order to prevent leakage of the transmitted signals to the receiving side, to prevent the occurrence of a “fake object” and other problems, in addition, on this basis it is difficult to build a simple structure.

Thus, there is a distance measuring device, such as shown in FIG. 23, which is based on the concept that a standing wave is generated if there is reflection (reflected wave) from the measurement object, when an electromagnetic wave that has only one frequency component is transmitted to the measurement object as a traveling wave, from an electromagnetic wave generating source; the device transmits an electromagnetic wave that has only one frequency component to the measurement object, simultaneously switching the frequency in steps, detects a standing wave generated when interference occurs between the transmitted wave and the wave reflected from the measurement object, and determines the distance between the detection point and the measurement object at based on the result of calculating the variable period of the amplitudes of this standing wave (see patent document 1).

The distance measuring device described in Patent Document 1 detects a standing wave generated when interference arises between a traveling wave that has only one frequency component and a reflected wave resulting from the reflection of the traveling wave from the measurement object; therefore, the distance measuring device does not need to prevent leakage of the transmitted signal to the receiving side, as in the case of the FMCW radar, etc., and a simple structure can be constructed. In addition, compared to pulsed radar, FMCW radar, and other radars, the distance measuring device disclosed in Patent Document 1 allows accurate measurements, even when measuring at close range.

The distance measuring device presented in Patent Document 1, however, is effective when the movement speed between the measurement object and the distance measurement device is relatively small, and the movement distance within the measurement time can be neglected, but when the movement speed between the measurement object and the distance measurement device is large, and the distance of movement within the measurement time cannot be neglected, with the help of such a device for measuring the distance it is difficult to obtain correctly measured values tions due to the Doppler effect.

To accurately measure the distance to a moving measurement object, a distance measuring device is used that increases and decreases the frequency of the signal, which has only one frequency component corresponding to a given stepwise frequency switching, transmits it in the form of a traveling wave, detects the amplitude of the standing wave generated as a result of interference between such a traveling wave and a reflected wave formed upon reflection of the traveling wave from the measurement object, calculates the signals that correspond to the detected amplitude, and determine the distance between the detection point and the measurement object (see, for example, patent document 2 and non-patent document 1).

The distance measuring device described in Patent Document 2 and Non-Patent Document 1 makes it possible to calculate signals that correspond to the amplitude of a standing wave generated as a result of interference between a traveling wave, the frequency of which increases and decreases in accordance with a predetermined step frequency change, and the reflected wave, and simultaneously measure the distance between the detection point and the measurement object, as well as the relative speed of the measurement object. Furthermore, in the case of the distance measuring device described in Patent Document 1, the distance between the detection point and the measurement object is determined by using a standing wave, and a simple construction of the distance measuring device can be obtained.

Patent Document 1: Publication No. 2002-357656 of the Pending Japanese Patent Application

Patent Document 2: Publication No. 2004-325085 of the Pending Japanese Patent Application

Non-Patent Document 1: Short-Range High-Resolution Radar Utilizing Standing Wave for Measuring of Distance and Velocity of a Moving Target, "FUJIMORI Shingo, UEBO Tetsuji, and IRITANI Tadamitsu, IEICE Transactions, vol. J87-B, No. 3, pp 437-445, March 2004.

SUMMARY OF THE INVENTION

Solved technical problems

In the distance measuring device presented in Patent Document 2 and Non-Patent Document 1, when the measured object is a single object, both the distance to the measured object and the relative speed can be measured with high accuracy; however, in the case when there are many measurement objects, the distance between the measurement objects is small and the speed difference is large, the distance to each measurement object cannot be determined unambiguously, and sometimes erroneous measurement results are obtained.

In addition, in a distance measuring device using a standing wave described in Patent Documents 1 and 2 mentioned above, as well as in Non-Patent Document 1, the frequency of the signal output from the signal sources changes stepwise, so that the signal (wave oscillations ) with a frequency f _a in a certain frequency band is output during the period Δt, as shown in FIG. 23, and thereafter, a signal with a frequency f _a + Δf is output for a period Δt. The signal output by the signal source is transmitted through a transmitting antenna, etc., is reflected by the measurement object and returns, reaching the detection point as a reflected wave. In this case, a traveling wave with a frequency f _a and a reflected wave that corresponds to a traveling wave with a frequency f _a form interference, i.e. superimposed on each other at the point of detection; as a result, a standing wave is generated. Thus, a standing wave is not generated from the moment a traveling wave with a frequency f _{a is} output, until the time when the reflected wave that corresponds to this frequency f _a reaches the detection point, and to generate a standing wave, it takes time from the moment of emission of a traveling wave with a frequency f _a , until a traveling wave with this frequency is reflected from the measurement object and the reflected wave reaches the detection point.

Therefore, the time interval Δt of the frequency switching cannot be made shorter than the time from the moment when the frequency has changed to the moment when a standing wave is generated. The distance measuring device, which uses a standing wave, therefore calculates the distance spectrum from the relationship between the received signal level and frequency, and obtains the distance to the measurement object, but when the measurement object moves with a relative velocity v, the peak of the distance spectrum deviates due to the Doppler effect , and as shown in FIG. 24, a measurement error of vΔt / ΔfΔf _{0 is} generated.

In view of these problems, the object of the claimed invention is to provide a distance measuring device and a distance measuring method that have the properties of "simple construction", "short distance measurement capabilities" and "small measurement errors", which would be similar to distance measuring devices in which a standing wave is used, and at the same time, in which the effect of the Doppler effect would be virtually absent.

Problem Solver

In a first aspect, in accordance with the present invention, there is provided a distance measuring device that includes a signal source for outputting a signal having a plurality of different frequency components within a certain frequency band, a transmission module for transmitting a signal in the form of a wave oscillation, a detection module mixed wave, designed to detect a mixed wave consisting of a traveling wave, including either a wave oscillation transmitted by the module a driver, or a signal output by a signal source, and a reflected wave representing a wave oscillation transmitted by a transmission module reflected from a measurement object, a frequency component analysis module for analyzing a frequency component of a mixed wave detected by a mixed wave detection module and a distance calculation module designed to determine the distance spectrum by performing, in relation to the data analyzed by the frequency component analysis module, an additional spectrum analysis ra and, thus, calculating the distance to the measurement object.

In the distance measuring method in accordance with the present invention, a signal having a plurality of different frequency components in a certain frequency band is transmitted as a wave oscillation, a mixed wave consisting of a traveling wave including either a transmitted wave oscillation or a signal is detected, and the reflected wave in the form of a transmitted wave oscillation reflected from the measurement object, analyzes the frequency component of the detected mixed wave, determine the distance spectrum by further exposing the data, roanalizirovannye using the frequency component analysis, spectral analysis, and thereby calculating the distance to the measurement object.

Therefore, due to the fact that a mixed wave consisting of a traveling wave and a reflected wave is detected and the distance to the measurement object is calculated based on the mixed wave, there is no need to separate the traveling wave (transmitted signal) and the reflected wave (received signal), and may A distance measuring device with a simple design and easy to use can be obtained. In addition, in a distance measuring device that uses a standing wave, a standing wave is not generated from the moment the frequency changes to the moment when the reflected wave that corresponds to this frequency does not return to the detection point and, in addition, the frequency must be switched in stages. and therefore, the distance measurement, in principle, cannot be performed at high speed, but in the claimed invention, which does not use a standing wave, the concept of frequency switching is not applied, and therefore, in principle, there is a time required for the switching frequency as compared with a distance measuring device that uses a standing wave, wherein the distance measuring apparatus according to the present invention provides a high speed distance measurement.

A signal source may include a plurality of single frequency generators, each of which generates a different component of a single frequency, and an adder that synthesizes the signals generated by the plurality of single frequency generators.

In addition, the signal source may include a single frequency generator that generates a single frequency component, and a modulator that modulates the signal generated by the single frequency generator.

In addition, the signal source may include a noise source that outputs a frequency component within a specific frequency band.

The frequency component analysis module may include an AD (AD, analog-to-digital) converter that converts the mixed wave detected by the mixed wave detection module into a digital signal, and a signal processor that analyzes the frequency components of the output of the AD converter and calculates the size of each frequency component.

In addition, the frequency component analysis module may include a plurality of bandpass filters and a level detection module that detects an output level of the bandpass filters.

The distance calculation module can calculate the distance spectrum by subjecting the analyzed data to Fourier analysis in the frequency component analysis module.

The plurality of mixed wave detection modules can be installed in different positions, the frequency component analysis module can analyze the frequency components for each mixed wave detected by the mixed wave detection modules, and the distance calculation module can calculate the distance spectrum using the analyzed frequency component data for the plurality of mixed waves obtained .

The second aspect in accordance with the claimed invention is directed to a distance measuring device that includes a signal source that outputs a frequency-modulated signal obtained by modulating the frequency of a carrier wave with a specific frequency by a signal with an arbitrary frequency, a transmission module that transmits a frequency-modulated signal as a wave oscillation, a mixed wave detection module that detects a mixed wave, consisting of a traveling wave, including either a wave oscillation a signal transmitted by a transmission module or a frequency-modulated signal output from a signal source and a reflected wave in the form of a wave oscillation transmitted by a transmission module reflected by a measurement object, an amplitude component detection module that detects an amplitude component of a mixed wave detected by a mixed wave detection module, and a distance calculation module that determines the distance spectrum by performing additional spectral analysis with respect to the amplitude component, d tektiruemogo detecting unit calculates an amplitude component and thus the distance to the measurement object.

In the distance measuring method, in accordance with the claimed invention, a signal obtained by frequency modulating a carrier wave with a specific frequency is transmitted by a signal with an arbitrary frequency, as a wave oscillation, a mixed wave consisting of a traveling wave including either transmitted wave oscillation is detected, or a frequency-modulated signal, and the reflected wave in the form of a transmitted wave oscillation reflected from the measurement object, detect the amplitude component of the detected mixed wave, about limit the distance spectrum, additionally subjecting the amplitude component to spectral analysis, and thus calculating the distance to the measurement object.

Therefore, due to the fact that a mixed wave consisting of a traveling wave and a reflected wave is detected and based on the mixed wave, the distance to the measurement object is calculated, it is not necessary to separate the transmitting and receiving antennas to prevent leakage of the traveling wave (transmitted signal) by receiving side, and a distance measuring device with a simple structure and simple to use can be obtained. In addition, in a distance measuring device using a standing wave, a standing wave is not generated from the moment the frequency is switched to the moment when the reflected wave that corresponds to this frequency does not return to the detection point and, in addition, the frequency must be switched in stages, and therefore, in principle, it is impossible to measure distance at high speed, but the claimed invention, which does not use a standing wave, does not contain the concept of frequency switching, and therefore, in principle, it does not require time is taken to switch the frequency, and compared to a distance measuring device that uses a standing wave, the distance measuring device in accordance with the present invention allows high-speed distance measurement.

The distance calculation module can calculate the distance spectrum by performing Fourier analysis for the amplitude component detected by the amplitude component detection module.

Many mixed wave detection modules can be installed in different positions, while the amplitude component detection module can detect amplitude components for each mixed wave detected by the mixed wave detection modules, the distance calculation module can calculate the distance spectrum using the analyzed amplitude component data of the set of mixed mixed waves .

In a third aspect, in accordance with the claimed invention, there is provided a distance measuring device that includes a signal source that outputs a dual modulated signal obtained by double modulating a carrier wave with a specific frequency by a second modulating signal, a pre-frequency modulated first modulating signal, a module a transmission that transmits a double modulated signal as a wave oscillation, a mixed wave detection module that detects a mixed wave, with consisting of a traveling wave, including either a wave oscillation transmitted by a transmission module or a double modulated signal output from a signal source, and a reflected wave in the form of a wave oscillation transmitted from a transmission module reflected from the measurement object, an amplitude component detection module, which detects the amplitude component of the mixed wave detected by the mixed wave detection module, a single frequency selection module that selects a specific single frequency component from the comp nents amplitude detected by the amplitude detection module component, the signal level detecting unit that detects a signal level obtained by the single frequency selection unit, and the distance calculation unit which calculates the distance to the measurement object by the level signal obtained by the signal level detecting unit.

In the distance measuring method, in accordance with the claimed invention, a double modulation signal is obtained, obtained by double modulation of a carrier wave with a certain frequency by a second modulating signal, a frequency modulated first modulating signal previously predetermined as a wave oscillation, and detects a mixed wave consisting of a traveling wave, including either a transmitted wave oscillation, or a signal with double frequency modulation, and a reflected wave in the form of a wave oscillation transmitted by the module soap has reflected from the measurement object, detecting the amplitude component detected mixed wave, selecting one specific frequency component from the amplitude component detected by the signal level of the selected frequency component and the calculated distance to the measurement object on the signal level.

Therefore, due to the fact that a mixed wave consisting of a traveling wave and a reflected wave is detected, and the distance to the measurement object is calculated based on the mixed wave, there is no need to separate the traveling wave (transmitted signal) and the reflected wave (received signal), and a distance measuring device can be obtained with a simple design and simple to use. In addition, in a distance measuring device that uses a standing wave, a standing wave is not generated from the moment the frequency is switched to the moment when the reflected wave corresponding to this frequency does not return to the detection point, and in addition, the frequency needs to be switched in stages. and therefore, the distance measurement, in principle, cannot be performed at high speed, but in the claimed invention, which does not use a standing wave, the concept of frequency switching is not applied and, therefore, in principle , there is no time required to switch the frequency, and compared with a distance measuring device that uses a standing wave, the distance measuring device in accordance with the present invention provides a high speed distance measurement.

The signal source may generate a first modulating signal that generates a first modulating signal, a second modulating signal modulated by the first modulating signal, and a carrier wave, respectively.

In addition, the signal source may have means for storing a second modulating signal, in which the second modulating signal is stored in advance.

Or, the signal source may have means for storing a second modulating signal, in which a second modulating signal is stored in advance, and means for generating a carrier wave that generates a carrier wave.

The first modulating signal may be a signal whose waveform is stepwise increasing or decreasing during a certain first period, and the second modulating signal may be a signal obtained by modulating a sawtooth wave with a shorter period than the first period modulated by the first modulating signal.

Effect of the invention

A distance measuring device and a distance measuring method in accordance with the claimed invention, formed as described above, detect a mixed wave consisting of a traveling wave and a reflected wave reflected from the measurement object; there is no need to prevent a traveling wave from leaking into the receiving antenna, a simple design can be obtained, and a distance measuring device with a low cost and a small size can be obtained.

In addition, when determining the distance spectrum from a mixed wave consisting of a traveling wave having many different frequency components and its reflected wave, the distance between the measurement object and the mixed wave detection module can be determined by the distance in the spectrum of which an amplitude peak occurs.

When the distance to the measurement object is measured using a standing wave, in principle, it is impossible to switch the frequency in a time shorter than the time required to form a standing wave from the moment the traveling wave frequency is switched, and therefore, the measurement is affected by the Doppler effect and generated measurement error, but in the claimed invention, in principle, there is no concept of frequency switching, so the observation time can be reduced to such a level that the effect of the Doppler effect can be practically ignored, and the correct distance can be measured regardless of the speed of movement and the direction of movement of the measurement object.

In addition, even when the distance between the plurality of measurement objects is small and the speed difference is large, which is difficult to measure with a distance measuring device using a standing wave, the position of each measurement object can be correctly measured.

In addition, the plurality of mixed wave detection modules are set in different positions, respectively, and the distance spectrum is determined by the plurality of mixed waves detected by the plurality of mixed wave detection modules; therefore, distance measurement can be performed with even greater reliability and greater accuracy.

In addition, when a double modulated signal is output from the signal source, there is no need to use a microprocessor with a high cost, etc., which allows you to perform spectrum analysis at a high speed, and the signal processor is designed as an envelope detector, quadratic detector, synchronous detector, quadrature a detector, a band-pass filter, a matched filter and other devices, and detects the intensity of the distance spectrum (signal level), and therefore, at low cost, a signal processor can be obtained that performs processing at a speed almost equal to the speed signal processor, which uses a microprocessor, etc. Thus, a distance measuring device with a low cost and a high signal processing speed can be obtained.

Brief Description of the Drawings

In FIG. 1 is a block diagram that explains the structure of a distance measuring device according to a first embodiment;

in FIG. 2 is an illustration of a distance measuring device that performs simulation in a first embodiment;

in FIG. 3 is a graph showing simulation results of measuring a distance to a measurement object located at a distance of 10 m and moving at a speed of 0 km / h in the first embodiment;

in FIG. 4 is a graph showing simulation results of measuring a distance to a measurement object located at a distance of 10 m and moving at a speed of +300 km / h in the first embodiment;

in FIG. 5 is a graph showing simulation results of measuring a distance to a measurement object located at a distance of 40 m and moving at a speed of -50 km / h in the first embodiment;

in FIG. 6 is a graph showing the results of modeling the measurement of the distance to the measuring object located at a distance of 5 m and moving at a speed of +100 km / h, as well as at a distance of 12.5 m and moving at a speed of -300 km / h, in the first an embodiment;

in FIG. 7 is an illustration of a distance measuring device equipped with a plurality of mixed wave detection modules in the first embodiment;

in FIG. 8 is a block diagram of a distance measuring device in accordance with a second embodiment;

in FIG. 9 is an illustration of a distance measuring device performing simulation in accordance with a second embodiment;

in FIG. 10 is a graph showing simulation results of measuring a distance to a measurement object located at a distance of 10 m and moving at a speed of 0 km / h in the second embodiment;

in FIG. 11 is a graph showing simulation results of measuring a distance to a measurement object located at a distance of 10 m and moving at a speed of +300 km / h in the second embodiment;

in FIG. 12 is a graph showing simulation results of measuring a distance to a measurement object located at a distance of 40 m and moving at a speed of -50 km / h in the second embodiment;

in FIG. 13 is a graph showing simulation results of measuring a distance to a measurement object located at a distance of 5 m and moving at a speed of +100 km / h and located at a distance of 12.5 m and moving at a speed of -300 km / h, in the second embodiment incarnations;

in FIG. 14 is an illustration of a distance measuring device equipped with a plurality of mixed wave detection modules in a second embodiment;

in FIG. 15 is a block diagram that explains the structure of a distance measuring device according to a third embodiment;

in FIG. 16 is a block diagram that illustrates another example of a signal source in a third embodiment;

in FIG. 17 is a graph that illustrates a waveform of a second modulating signal;

in FIG. 18 is a graph that illustrates a waveform of a first modulating signal;

in FIG. 19 is an illustration of a distance measuring device using a quadrature detector in a third embodiment;

in FIG. 20 is a graph that presents simulation results of measuring a distance to measuring objects located at a distance of 12 m and 20 m in a distance measuring device using a quadrature detector in a third embodiment;

in FIG. 21 is an illustration of a distance measuring device in which bandpass filters are used in a third embodiment;

in FIG. 22 is a graph that presents simulation results of distance measurement for measuring objects located at a distance of 12 m and 20 m in a distance measuring device in which bandpass filters are used in the third embodiment;

in FIG. 23 is an illustration of a change in frequency of a signal source in a distance measuring device in which a standing wave is used; and

in FIG. 24 is an illustration explaining the effect of the Doppler effect in a distance measuring device using a standing wave.

Brief Description of Reference Numbers

1. Signal source

2. Transmission module

3. Mixed wave detection module

4. Frequency component analysis module

5. Distance calculation module

6. Object of measurement

7. Signal processor

8. Down-converter

8a. Heterodyne

8b. Mixer

9. Signal source

9a. Carrier wave signal source

9b. Modulation source

10. The module for detecting the amplitude component

11. Distance calculation module

12. Signal processor

13. Signal source

13a. Carrier wave signal source

13b. Source of the second modulating signal

13c. The source of the first modulating signal

13d. Means for generating a second modulating signal

13e. Means for storing the second modulating signal

13f. Dual Modulation Signal Generator

13g. Dual Modulation Signal Storage

14. Signal processor

15. The module for detecting the amplitude component

16. Single frequency selection module

17. Signal strength detection module

18. Distance calculation module

19. Signal processor

20. Envelope detector

21. Quadrature detector

22. Level detection module

23. Distance calculation module

24. Signal processor

25. Envelope detector for detecting the amplitude component

26. Band-pass filter

27. Envelope detector for detecting signal strength

28. Distance calculation module

DETAILED DESCRIPTION OF THE INVENTION

The distance measuring device and the distance measuring method related to the claimed invention are presented in figures 1, 8 and 15, and are intended for transmitting signals output through the signal sources 1, 9 and 13 from the transmission unit 2, in the form of a wave oscillation, and detecting a mixed a wave without separation of the reflected wave V _{R of} this wave oscillation (traveling wave V _T ) reflected from the measurement object 6 in the mixed wave detection unit 3.

The signal source in the claimed invention outputs a signal that has many different frequency components in a certain frequency band, outputs a frequency-modulated signal obtained as a result of frequency modulation of a carrier wave at a certain frequency by an arbitrary periodic signal, or outputs a double-modulated signal resulting from a double frequency modulation of the carrier wave with a certain frequency by the second modulating signal, which was previously frequency-modulated by the first modulating signal. Thus, the signals output by the sources 1, 9 and 13 of the signal are signals that constantly have many different frequency components.

In addition, the traveling wave in the claimed invention is a wave oscillation, which represents the signals output from the signal sources 1, 9 and 13, which are transmitted by the transmission unit 2, or the signals output from the signal sources 1, 9 and 13. Thus, the traveling wave in the claimed invention is a wave oscillation or signal (signal wave), which constantly has many frequency components. In addition, the reflected wave related to the claimed invention, is a wave oscillation, constantly having many frequency components and reflected from the object 6 of the measurement.

The mixed wave in the claimed invention is also a wave oscillation obtained by mixing (synthesis) of a traveling wave and a reflected wave. Thus, the wave oscillation obtained by superimposing a traveling wave having a plurality of frequency components on a reflected wave having a plurality of frequency components is a mixed wave in the claimed invention, and this does not mean a wave oscillation in which a plurality of wave oscillations (waves) are superimposed. having single frequency components.

In the following embodiments, an explanation is given of an electromagnetic wave, mentioned as an example of a wave oscillation, but wave oscillations of light, sound wave, current, wave in a material that propagates inside the material, and others are wave oscillations in accordance with the claimed invention.

It should be noted that in a distance measuring device that uses a standing wave, as presented in the aforementioned patent documents 1 and 2 and non-patent document 1, etc., the signals output from the signal sources are signals whose frequency is switched, and in which the single frequency component varies stepwise with time, as shown in FIG. 23, and do not represent signals that constantly have many different frequency components, as in the case of the claimed invention. In addition, the amplitude of wave oscillations generated as a result of interference between a traveling wave transmitted on the basis of a signal having a single frequency component and a reflected traveling wave having this single frequency component that was reflected from the measurement object does not change in time and receives different values depending on the position in space. In particular, the amplitude is represented by a periodic function with respect to position, and this is called a standing wave.

In the interference between a traveling wave, which is based on signals having a plurality of frequency components, and a reflected wave, as in the case of the claimed invention, the relationship between the position in space and the amplitude of the mixed wave changes in time and forms a phenomenon different from the standing wave.

Therefore, the distance measuring device, which relates to the claimed invention, uses physical phenomena that are different from the phenomena used in the distance measuring device, which is based on a standing wave, and they differ fundamentally.

The first embodiment

The technical solution of the first embodiment of the distance measuring device and the distance measuring method in accordance with the claimed invention will be described below.

(Technical Solution 1)

In FIG. 1 is an illustration that explains the structure of a distance measuring device related to the claimed invention. The distance measuring device related to the claimed invention transmits a signal (traveling wave V _T ) output from the signal source 1, in the form of a wave oscillation from the transmission unit 2 to the measurement object 6, detects a mixed wave V _C consisting of a reflected wave V _Rk , which was reflected by the kth measurement object 6, and the traveling wave V _T , in the mixed wave detection module 3, analyzes the mixed wave component (a (f, x _s )) in the frequency component analysis module 4, calculates the spectrum R (x) distances in distance calculation module 5 And measures the distance to the measurement object 6.

A signal source 1 outputs a signal having a plurality of different frequency components in a particular frequency band, and continuously outputs signals having two or more frequency components. As a specific example, the signal source 1 is made using a plurality of single frequency generators that generate signals of different single frequency components, and an adder that synthesizes the signals of the single frequency components generated by the plurality of single frequency generators, and signals constantly having two or more frequency components , output from source 1 of the signal. In addition, the signal source 1 can be performed using a single frequency generator that generates a single frequency component, and a modulator that superimposes certain modulation, such as frequency modulation, amplitude modulation and other types of modulation, to the signal generated by this single frequency generator, and in this case, signals having different frequency components in a certain frequency band can be output. In addition, the signal source 1 can be performed using a noise source that outputs frequency components in a specific frequency band. A noise source that outputs frequency components in a specific frequency band, for example, can be obtained using a band-pass filter that transmits signals in a specific frequency band, consisting only of signals output from a noise source.

The transmission module 2 is a bi-directional element, such as an antenna (or electrode), etc., which transmits a signal output from the signal source 1 as a wave oscillation. In the case where the mixed wave detection module 3 is located between the signal source 1 and the transmission module 2, the transmission module 2 can fulfill the role of receiving the reflected wave. The transmission unit 2 outputs the wave oscillation of the frequency component output from the signal source 1, and the output wave oscillation is transmitted to the measurement object 6.

Thus, the traveling wave V _t in the claimed invention denotes the wave oscillation transmitted from the transmission unit 2, and the signal output from the signal source 1.

Therefore, in the case where the mixed wave consisting of the signal from the signal source 1 and the reflected wave signal returned through the transmission unit 2 is detected by the mixed wave detection unit 3, the signal from the signal source 1 becomes a traveling wave V _t .

The mixed wave detection unit 3 detects a mixed wave V _C consisting of a traveling wave V _T and a reflected wave V _Rk . This mixed wave detection module 3 can be made by connecting an omnidirectional connector for detecting a mixed wave V _C consisting of a traveling wave V _T output from the signal source 1 and a reflected wave V _Rk returned through the transmission module 2 in the middle of the supply feeder, which connects the signal source 1 to the transmission module 2. In addition, a receiving antenna (or electrode) for detecting a mixed wave V _C consisting of a traveling wave V _T and a reflected wave V _Rk is installed in the space between the transmission unit 2 and the measurement object 6 and is designated as the mixed wave detection unit 3.

The frequency component analysis module 4 analyzes the mixed wave frequency component V _c detected by the mixed wave detection module 3. It is also possible to execute the frequency component analysis module 4 using a plurality of bandpass filters and a level detection module that detects an output level of the bandpass filters and analyzes the intensity of each frequency component.

In addition, the frequency component analysis module 4 may be performed on the basis of an AD converter that converts the mixed wave detected by the mixed wave detection module 3 into a digital signal, and a signal processor in which software is installed that exposes the digital signal representing the mixed wave, derived from the AD converter, analyzing the frequency component, such as the Fourier transform, etc., to calculate the intensity (absolute value) a (f, x _s ) of each frequency component.

Thus, the mixed wave detected by the mixed wave detection module 3 can be output directly to the AD converter, but the down-converter 8 (see Fig. 2) can be installed between the mixed wave detection module 3 and the AD converter, and the frequency can be introduced into the AD converter after lowering the frequency. As for the down-converter 8, the known down-converter is sufficient, and, for example, the down-converter can be made with a local oscillator 8a that generates a frequency that needs to be down-converted and a mixer (frequency converter) 8b, which mixes the mixed wave V _c detected by the mixed wave detection unit 3 and a periodic local oscillator signal 8a for down-converting to the desired frequency.

The distance calculation module 5 subjects the data analyzed by the frequency component analysis module 4 to spectral analysis to obtain a distance spectrum, calculates the intensity of this distance spectrum, and calculates the distance to the measurement object 6 based on the intensity of the distance spectrum peak. As a spectrum analysis method, the spectrum is analyzed using a non-parametric technique represented by the Fourier transform, or a parametric technique such as AR modeling, or another appropriate spectrum analysis technique.

(Principle 1 of measurement)

The measurement principle will be described with reference to FIGS. 1 and 2 for a distance measuring device and a distance measuring method that relate to the claimed invention, as follows.

When the traveling wave output from signal source 1 has a frequency component with a frequency band from f ₀ · f _w / 2 to f ₀ + f _w / 2, and the intensity of each frequency component is A (f), and the phase is represented as θ (f), a traveling wave V _T at time t elapsed time and in position x from the start of measurement can be expressed by the following Equation (1):

Lv. (1)

where f denotes frequency and c denotes the speed of light, and any point on the x axis represents x = 0.

The path d _k denotes the distance to the k-th measured object 6; v _{k the} speed of light and y _k and φ _k represent the size and phase of the reflection coefficient, respectively; then the reflected wave V _Rk from the measurement object 6 can be expressed by the following Equation (2), where, k = 1, 2 ...:

Lv. (2)

In this case, the mixed wave signal V _c observed in the mixed wave detection unit 3, located at position x = x _s , is expressed as follows. (3):

Lv. (3)

The mixed wave V _C detected by the mixed wave detection unit 3 is decomposed into each frequency component using a band-pass filter. Or, as shown in FIG. 2, the mixed wave Vc is converted to a digital signal using an AD converter (S100), and this digital signal is decomposed into each frequency component by analyzing the frequency component, such as the Fourier transform (S101).

The decomposed component V _C (f, t, x _s ) of frequency f is an integrable function (an equation that must be integrated) in Eq. (3) and is expressed as follows. (four):

Lv. (4)

The amplitude of the decomposed frequency component f can be expressed as follows. (5).

Lv. (5)

where, it can actually be assumed that the intensity of the reflected wave is extremely small, and therefore it can be approximated as Y _k << 1.

Now, if t is made small enough, we can consider v _k t≡0, (as in the simulation case described below, even when the observation time t = 3.5 [μs] and the speed v _k = 300 [km / h], v _k t≡0.29 [mm], and vkt≡0 can be taken), and the amplitude of the decomposed frequency component f can be approximated, for example, as in the next Eq. (6):

Lv. (6)

Now A (f) denotes the frequency response of signal source 1, and it can be easily recognized, and therefore, it can be considered known. In the case when A (f) can be considered as a constant A, we obtain

Lv. (7)

Or in the case when A (f) is not a constant (for example, in the case when a noise source is used), normalization of Ur. (6) by A (f) allows us to obtain

Lv. (8)

The value of the constant A in the abovementioned (7) does not contain distance information. Therefore, if A = 1, Eq. (7) becomes the same as Eq. (8), and Eq. (8) is used below as an equation that expresses the amplitude.

We have determined that Ur. (8) is a periodic function that has a period c / 2 (d _k · x _s ) for frequency f. Therefore, if it is subjected to spectral analysis using non-parametric technology represented, for example, by Fourier transform, or parametric technology, such as AR modeling, etc., the distance d _k · x _s from the mixed wave detection unit 3 to object of measurement.

An example of distance calculation using the Fourier transform is presented as follows.

In the Fourier transform formula

Lv. (9),

the changes were made ω / 2τ → 2x / c, t → f, and f (t) → a (f, x _s ). As a result, the distance spectrum R (x) can be found as follows (S103 (see FIG. 2)).

Lv. (10)

where, S _a (z) = sin (z) / z.

According to ur. (10), intensity R (x) (intensity of the distance spectrum) | R (x) | takes the peak value at x = 0, ± (d _k · x _s ). In fact, the limit is to x> 0, since the distance d _k · x _s from the mixed wave detection unit 3 to the measurement object 6 is positive; then the value of x when | R (x) | takes a peak value, represents the distance d _k · x _s from the mixed wave detection unit 3 to the measurement object 6. Thus, when determining the value of x, in which the value | R (x) | become a peak, it is possible to determine the position from the mixed wave detection unit 3 to the measurement object 6 (S104 (see FIG. 2)).

As described above, in the distance measuring device and in the distance measuring method, in accordance with the claimed invention, a mixed wave consisting of a traveling wave and a reflected wave reflected from the measurement object is detected, so there is no need to separate the traveling wave and the reflected wave, and may be a simple design is obtained, and a measuring device can be built for measurements at short distances and at low cost.

In addition, when determining the distance spectrum from a mixed wave consisting of a traveling wave having many different frequency components and its reflected wave, one can determine the distance between the measurement object and the mixed wave detection module from the distance at which the intensity of the distance spectrum takes on a peak value.

When the distance to the measurement object is measured by using a standing wave, it is in principle impossible to make the observation time shorter than the time during which the standing wave is formed after switching the frequency of the traveling wave, while the Doppler effect acts on the peak of the distance spectrum and a measurement error is generated but, in the claimed invention, in principle, there is no concept of frequency switching, and the observation time can be reduced to a level at which the Doppler effect can actually be ignored, and yanie can be accurately measured.

(Simulation l)

Further, based on the measurement principle 1 described above, a simulation was performed with the distance measuring device shown in FIG. 2.

The distance measuring device shown in FIG. 2, has a signal source 1, which constantly outputs a signal including 24,000 GHz - 24,075 GHz components, and a transmission module 2, which transmits a traveling wave V _T , which constantly includes components in a certain frequency band, to objects 6, ... 6 measurements. And the distance measuring device has a mixed wave detection module 3, which detects a mixed wave V _C (t, 0) consisting of a reflected wave V _Rk reflected by the k-th measurement object 6 and a traveling wave V _T. Thus, the mixed wave detection module 3 is located at the point x _s = 0. The detected mixed wave V _{C is} downconverted to a range from 0 to 75 MHz using a down converter 8. V _C after downconversion is converted to a digital signal using an AD converter (S100), and V _C (f, t, 0) converted to a digital signal is Fourier transformed to decompose it into each frequency component (S101). To determine the amplitude of each frequency component, the absolute value of the mixed wave V _c (f, t, 0) decomposed into the frequency components (S102) is calculated, and then the normalized amplitude a (f, 0) is determined. This normalized amplitude a (f, 0) is subjected to spectral analysis to determine the spectrum R (x) of the distance (S103), and from the peak amplitude (intensity) of the spectrum R (x) of the distance, the position of the measurement object 6 is calculated (S104). In this case, let the direction in which the measurement object 6 is removed from the distance measuring device be positive, and the direction in which the measurement object approaches the distance measuring device will be negative.

In modeling the distance measuring device shown in FIG. 2, a mixed wave consisting of a traveling wave and a reflected wave was observed for 3.5 μs (t = 3.5 [μs]).

In the simulation, a signal uniformly including components from 24,000 GHz to 24,075 GHz, output from the signal source, is designated as a traveling wave, and the mixed wave V _C (t, 0) was calculated in accordance with Eq. (3). Then the mixed wave V _{C was} multiplied by a complex sine wave with a frequency of 24 GHz and the value V _C converted with decreasing frequency was obtained. Thus, the mixed wave V _{C was} converted with decreasing frequency to a range from 0 to 75 MHz.

Then, the down-converted frequency V _C was subjected to Fourier transform to determine Ur. (8) a ((f, 0)) in absolute value, and a (f, 0) were subjected to the Fourier transform in accordance with Eq. (10), to obtain the spectrum R (x) of the distance and the size of the spectrum (| R (x) |) of the distance.

(Simulation 1-1)

Fig. 3 shows graphs that simulate a distance measurement when the measurement object 6 remains stationary at a distance of 10 m from the mixed wave detection module 3 and for a speed of 0 km / h. In FIG. Figure 3 (a) shows the waveform depending on the time of the mixed wave after conversion with decreasing frequency (traveling wave + reflected wave) and a graph that shows the instantaneous value at each moment of time of the measurement period (graph V _C (t, 0) after conversion with decreasing frequency). In FIG. 3 (b) shows a graph a (f, 0) presented in Eq. (8), and the normalized amplitude of each frequency component is shown. In FIG. 3 (c) shows a graph that represents the relationship between the distance and the spectrum intensity | R (x) | the distances during processing a (f, 0) obtained in FIG. 3 (b) using spectral analysis. As can be seen in FIG. 3 (c), the intensity of the distance spectrum has a large peak value at a distance of 10 meters. Based on this, in a stationary state, you can correctly measure the distance.

(Simulation 1-2)

In FIG. 4 shows graphs that simulate distance measurement when the measurement object 6 moves at a distance of 10 m from the mixed wave detection module 3 at a speed of +300 km / h. In FIG. 4 (a) shows the waveform depending on the time of the mixed wave after conversion with decreasing frequency (traveling wave + reflected wave), and a graph is shown that represents the instantaneous value at each moment of time of the measurement period (graph V _C (t, 0) after downconversion). In FIG. 4 (b) shows a graph a (f, 0) presented by Eq. (8), and the normalized amplitude of each frequency component is indicated. In FIG. 4 (c) shows a graph that represents the relationship between the distance and the spectrum intensity | R (x) | the distance after processing a (f, 0) determined in FIG. 4 (b) using spectral analysis. As can be seen in FIG. 4 (c), the intensity of the distance spectrum has a large peak value at a distance of 10 m. Based on this, even when the measurement object moves at a speed of +300 km / h, you can correctly measure the distance, as in the case of simulation 1-1.

(Simulation 1-3)

In FIG. 5 shows graphs that simulate distance measurement when the measurement object 6 moves at a distance of 40 m from the mixed wave detection module 3 and at a speed of -50 km / h. In FIG. 5 (a) shows the waveform depending on the time of the mixed wave after conversion with decreasing frequency (traveling wave + reflected wave), and a graph is shown that represents the instantaneous value at each moment of time of the measurement period (graph V _C (t, 0) after downconversion). In FIG. 5 (b) shows a graph a (f, 0) presented by Eq. (8), and the normalized amplitude of each frequency component is indicated. In FIG. 5 (c) is a graph representing the relationship between the distance and the spectrum intensity | R (x) | distance, by processing a (f, 0) obtained in FIG. 5 (b) using spectral analysis. As can be clearly seen in FIG. 5 (c), the intensity of the distance spectrum has a large peak value at a distance of 40 m. On this basis, even when the distance, speed of movement and direction of movement to the measurement object change, you can correctly measure the distance.

(Simulation 1-4)

In FIG. 6 shows graphs that simulate distance measurement when there are two measurement objects 6 and one measurement object 6 moves at a distance of 5 m from the mixed wave detection unit 3 and at a speed of +100 km / h, while the other measurement object 6 moves at a distance of 12.5 m from the mixed wave detection module 3 and at a speed of -300 km / h. In FIG. 6 (a) shows the waveform depending on the time of the mixed wave after conversion with decreasing frequency (traveling wave + reflected wave), and a graph is presented that shows the instantaneous value at each moment of time of the measurement period (graph V _C (t, 0) after downconversion). In FIG. 6 (b) shows a graph a (f, 0) presented by Eq. (8) and the normalized amplitude of each frequency component is indicated. In FIG. 6 (c) shows a graph that represents the relationship between the distance and the spectrum intensity | R (x) | distance, by processing a (f, 0) determined in FIG. 6 (b) using spectral analysis. As can be seen in FIG. 6 (c), the intensity of the distance spectrum has large peak values at distances of 5 m and 12.5 m. Based on this, even when there are many measurement objects, you can correctly measure distances. Even when the measurement object moves a short distance of 10 m or less, the distance can also be measured correctly. In addition, even in the case where the distance to the plurality of measurement objects decreases and the speed difference is large, which is difficult to measure using a distance measuring device that uses a standing wave, the position of each measurement object can be correctly measured.

As can be seen from the above simulation 1-1 - 1-4, the distance to the measurement object can be measured regardless of the speed of the measurement object. In addition, even when the distance to a plurality of measurement objects becomes small and the speed difference is large, the position of each measurement object can be measured correctly.

In the above description, a mixed wave is detected using one mixed wave detection module 3, but as shown in FIG. 7, a plurality of mixed wave detection modules 3, ..., 3 can be located at different positions x _s1 , ... x _sN , which are different from each other. Mixed waves V _C detected by a plurality of mixed wave detection modules 3, ..., 3 are thus subjected to AD conversion using an AD converter for each mixed wave detection module 3 (S110), mixed wave signals converted to digital signals are subjected to Fourier transform (S111), and the absolute value is calculated to obtain the amplitude a (f, x _si ) (i is 1, 2, ..., N, ...) for each mixed wave detection unit 3. When determining the difference between any two amplitudes (for example, a (f, x _s1 ) and a (f, x _s2 )), the optional DC component is eliminated (the first element of Eq. (8)), (S113), and each amplitude a (f, x _si ) with an optional remote DC component is subjected to spectral analysis to obtain a distance spectrum (S114), and after averaging each distance spectrum (S115), the distance to the measurement object 6 is calculated based on the peak of the distance spectrum size (S116). This can be obtained by providing, for example, a means of eliminating a DC component that determines the difference of any two amplitudes and removes an unnecessary DC component, and a means of averaging the distance spectrum, which calculates the average value of the set of distance spectra for the distance calculation module 5.

Therefore, in the case where a plurality of mixed wave detection modules 3 are mounted so that a signal processor is formed, as shown in FIG. 7, optional DC components can be removed. In addition, the distance spectra obtained for each amplitude a (f, x _si ) average, reduce the noise components, and at the same time, the distance can be more accurately measured.

Second Embodiment

The structure of the second embodiment of the distance measuring device and the distance measuring method related to the claimed invention will be described below.

(Technical Solution 2)

In FIG. 8 is an illustration that illustrates the structure of a distance measuring device related to the claimed invention. A distance measuring device related to the claimed invention transmits a signal output from a signal source 9 in the form of a wave oscillation from a transmission unit 2 to a measurement object 6, detects a mixed wave V _c consisting of a reflected wave V _Rk reflected by the k-th object 6 measuring, and the traveling wave V _T in the mixed wave detection unit 3, detects the mixed wave amplitude component a (t, x _s ) in the amplitude component detection unit 10, calculates the distance spectrum R (x) in the distance calculation unit 11, and measures the distance Charm to the object of 6 dimensions.

The signal source 9 outputs a frequency-modulated signal obtained by frequency modulating a carrier wave with a specific frequency by an arbitrary periodic signal, and constantly outputs a signal having two or more frequency components. As a specific example, as shown in FIG. 9, the signal source 9 is made using a carrier wave signal source 9a that transmits a carrier wave signal with a specific frequency and a modulating signal source 9b that modulates the carrier wave signal with an arbitrary periodic signal, and a frequency modulated signal is output from this signal source 9. As another specific example, the signal source 9 may be implemented using a frequency-modulated signal generating means (not shown) equipped with a microprocessor and means for storing a frequency-modulated signal (not shown), in which data for outputting the frequency-modulated signal is stored with an instantaneous frequency f ₀ + f _D · m (t), and the data stored in the means for storing the frequency-modulated signal is read by means of generating a frequency-modulated signal, and m, a frequency-modulated signal can be generated.

The transmission module 2 is a bi-directional element, such as an antenna (or electrode), etc., which transmits a signal output from the signal source 9 in the form of a wave oscillation. In the case where the mixed wave detection module 3 is located between the signal source 9 and the transmission module 2, the transmission module 2 can fulfill the role of receiving the reflected wave. The transmission unit 2 outputs a wave oscillation with a frequency component output from the signal source 9 and the output wave oscillation is transmitted to the measurement object 6.

Thus, the traveling wave V _t in the claimed invention denotes the wave oscillation transmitted from the transmission unit 2, and the signal output from the signal source 9.

Therefore, in the case where the mixed wave, consisting of the signal of the signal source 9 and the reflected wave signal returned through the transmission unit 2, is detected by the mixed wave detection unit 3, the signal from the signal source 9 becomes a traveling wave V _T.

The mixed wave detection unit 3 detects the mixed wave V _{C of the} traveling wave V _T and the reflected wave V _Rk . This mixed wave detection module 3 can be accomplished by installing an omnidirectional connector for detecting a mixed wave V _C consisting of a traveling wave V _T output from a signal source 9 and a reflected wave V _Rk returned through a transmission module 2 connected to the middle of the power feeder which connects the signal source 9 to the transmission unit 2. In addition, a receiving antenna (or electrode) for detecting a mixed wave V _C consisting of a traveling wave V _T and a reflected wave V _{Rk is} installed in the space between the transmission unit 2 and the measurement object 6, and is designated as the mixed wave detection unit 3.

The amplitude component detection module 10 detects the amplitude component of the mixed wave V _C detected by the mixed wave detection module 3, and includes an envelope detector, a quadratic detector, a synchronization detector, a quadrature detector, and the like.

The distance calculation module 11 subjects the amplitude component detected by the amplitude component detection module 10 to spectral analysis to obtain a distance spectrum, calculates the intensity of this distance spectrum, and calculates the distance to the measurement object 6 based on the peak of the distance spectrum intensity. As a spectral analysis method, the spectrum is analyzed using a non-parametric technique represented by a Fourier transform, or a parametric technique such as AR modeling, etc., or another appropriate spectral analysis technique.

(Principle 2 of measurement)

Consider Figs. 8 and 9, with reference to which a measurement principle of a distance measuring device and a distance measurement method related to the claimed invention will be described as follows.

When the signal source 9a includes a carrier wave signal source 9a with a frequency f ₀ and a modulation signal source 9b that modulates the carrier wave of a given carrier wave signal source 9a, the traveling wave V _T with the elapsed time t from the start of measurement and in position x becomes frequency-modulated undamped wave, which is expressed by the following Eq. (11):

Lv. (11)

where t denotes the time elapsed from the start of the measurement, and m (t) is a modulated signal, which is an arbitrary periodic function with an amplitude of 1. Let f _D denote the maximum frequency shift in frequency modulation, and f ₀ denotes the center frequency. Therefore, the instantaneous frequency of the traveling wave V _T (t, x) is f ₀ + f _D · m (t). In addition, c denotes the speed of light, and θ denotes a phase, and any point on the x axis represents x = 0.

Let d _k denote the distance to the k-th measurement object 6, v _k speed, and y _k and φ _k denote the size and phase of the reflection coefficient, respectively; then the reflected wave from the measurement object 6 can be expressed as follows. (12), where k = 1, 2,

Lv. (12)

In this case, the mixed-wave signal V _C observed in the mixed-wave detecting unit 3, located at position x = x _s , is expressed as follows. (13):

Lv. (13)

And the amplitude of V _C is expressed as follows. (fourteen).

Lv. (14)

In practice, we can assume that the size of the reflected wave is extremely small y _k << 1, and the coefficient of the second degree y _k and higher can be ignored, since they are approximately equal to zero. Therefore, it can be approximated as the following Eq. (15)

Lv. (15)

Now, if t is made small enough, we can assume that v _k t≡0 (as in the modeling case described below, even when the observation time t = 20 [μs] and the speed v _k t = 300 [km / h], v _k t≡0.1.7 [mm], and we can assume that v _k t≡0), the amplitude of V _C can be approximated, as in the next Lv. (16) and the influence of speed v _k can be excluded:

Lv. (16)

In addition, when approximating, as in the next Lv. (17)

Lv. (17)

Ur (16) becomes the next Lv. (eighteen).

Lv. (18)

where A = 1, since the constant A does not contain information in the claimed invention.

Then, it was determined that Ur. (18) is a periodic function that has a period c / 2 (d _k · xs) for the instantaneous frequency f ₀ + f _D · m (t). Therefore, if it is subjected to spectral analysis using a non-parametric technique represented, for example, by the Fourier transform or a parametric technique, such as AR modeling, etc., the distance d _k · xs from the mixed wave detection unit 3 to the measurement object 6 can be obtained 6.

An example of calculating the distance using the Fourier transform is presented below.

In the formula (9) of the Fourier transform, the substitution f (t) → a (f, x _s ), ω / 2τ → 2x / c, and t → instantaneous frequency f ₀ + f _D · m (t) are performed. Since df = f _D dm (t) the spectrum R (x) of the distance can be determined in accordance with the following Eq. (19).

Lv. (19),

where, Sa (z) = sin (z) / z.

According to ur. (19), size R (x) (distance spectrum intensity) | R (x) | takes the peak value at the point x = 0, ± (d _k · x _s ). In practice, the limit is x> 0, since the distance d _k · x _s from the mixed wave detection unit 3 to the measurement object 6 is positive; then the value of x in which | R (x) | takes a peak value, represents the distance d _k · x _s from the mixed wave detection unit 3 to the measurement object 6.

As described above, in the distance measuring device and in the distance measuring method associated with the claimed invention, a mixed wave consisting of a traveling wave and a reflected wave reflected from the measurement object is detected, so there is no need to separate the traveling wave and the reflected wave, and can be obtained simple design, and a distance measuring device with small cost and small size can be built.

In addition, when determining the distance spectrum from a mixed wave consisting of a traveling wave having many different frequency components and its reflected wave, one can determine the distance between the measurement object and the mixed wave detection module from the distance at which the intensity of the distance spectrum takes on a peak value.

When the distance to the measurement object is measured using a standing wave, it is in principle impossible to make the observation time shorter than the time during which a standing wave is formed after switching the frequency of the traveling wave, while the Doppler effect acts on the peak of the distance spectrum and a measurement error is generated, but in the claimed invention, in principle, there is no concept of frequency switching, and the observation time can be reduced to a level at which the Doppler effect can actually be ignored, and you can accurately measure the distance.

(Simulation 2)

Further, based on the previous measurement principle 2, a simulation is performed with the distance measuring device shown in FIG. 9.

The signal source 9 of the distance measuring device shown in FIG. 9 has a carrier wave signal source 9a that outputs a carrier wave signal with a frequency f ₀ = 24.0375 GHz and a modulating signal source 9b, whose modulating signal m (t) is a sinusoidal oscillation with a frequency of 50 kHz and with a maximum frequency shift f _D = 37.5 MHz, and outputs a signal with an instantaneous frequency f ₀ + f _D · m (t). Running wave V _T expressed by Lv. (11) transmit from transmission module 2. The mixed wave V _C (t, 0), consisting of the reflected wave V _Rk , reflected from the k-th measurement object 6, and the traveling wave V _T , are detected using the mixed wave detection module 3. A mixed wave V _{c is} observed for 1 period of the modulated signal m (t). Therefore, t = 1/50 [kHz] = 20 [μs]. Thus, the mixed wave detection unit 3 is located at the point x _s = 0. In addition, let the direction in which the measurement object 6 moves away from the distance measuring device be positive and the direction in which the object approaches the distance measurement device to be negative.

A detectable mixed wave V _{C is} subjected to envelope detection using an envelope detector, and a mixed wave amplitude component a (t, 0) is detected (S120). When the component a (t, 0) of the amplitude of the mixed wave is detected, it is converted into a digital signal using the AD converter (S121). The digitized amplitude a (t, 0) is subjected to spectral analysis and the distance spectrum R (x) is determined (S122). From the peak of the found intensity of the distance spectrum, the position of the measurement object 6 is calculated (S123).

(Simulation 2-1)

In FIG. 10 is a graph that simulates a distance measurement when the measurement object 6 remains stationary at a distance of 10 m from the mixed wave detection unit 3 and has a speed of 0 km / h. In FIG. 10 (a) is a graph showing the amplitude a (t, 0) of the modulating signal m (t) and the mixed wave. In FIG. 10 (b) shows the intensity of the distance spectrum after performing spectral analysis on this basis. As can be seen in FIG. 10 (b), the intensity of the distance spectrum has a large peak value at a distance of 10 m. Based on this, in a stationary state, it is possible to correctly measure the distance at a short distance of tens of meters or less.

(Simulation 2-2)

In FIG. 11 shows graphs that simulate distance measurement when the measurement object 6 moves at a distance of 10 m from the mixed wave detection module 3 at a speed of +300 km / h. In FIG. 11 (a) is a graph showing the amplitude a (t, 0) of the modulating signal m (t) and the mixed wave. In FIG. 11 (b) shows the intensity of the distance spectrum after performing spectral analysis on this basis. As can be seen in FIG. 11 (b), the intensity of the distance spectrum has a large peak value at a distance of 10 m. Based on this, even when the measurement object moves at a speed of +300 km / h, you can correctly measure the distance, as in the case of simulation 2-1.

(Simulation 2-3)

In FIG. 12 is a graph that simulates a distance measurement when the measurement object 6 moves at a distance of 40 m from the mixed wave detection unit 3 and at a speed of -50 km / h. In FIG. 12 (a) is a graph showing the amplitude a (t, 0) of the modulated signal m (t) and the mixed wave. In FIG. 12B shows the intensity of the distance spectrum after performing spectral analysis on this basis. As can be seen in FIG. 12 (b), the intensity of the distance spectrum has a large peak value at a distance of 40 m. On this basis, even when the distance, the speed of movement, and the direction of movement of the measurement object change, you can correctly measure the distance.

(Simulation 2-4)

In FIG. 13 shows graphs that simulate distance measurement when there are two measurement objects 6 and 6, and one measurement object 6 moves at a distance of 5 m from the mixed wave detection unit 3 and has a speed of +100 km / h, while the other object 6 The measurement moves at a distance of 12.5 m from the mixed wave detection module 3 and has a speed of -300 km / h. In FIG. 13 (a) is a graph showing the amplitude a (t, 0) of the modulating signal m (t) and the mixed wave. In FIG. 13B shows the intensity of the distance spectrum after performing spectral analysis on this basis. As can be seen in FIG. 13 (b), the intensity of the distance spectrum has large peak values at distances of 5 m and 12.5 m. Based on this, even when there are many measurement objects, you can correctly measure the distance. Furthermore, even at a short distance of 10 m or less, it is possible to correctly measure the distance. In addition, even when the distance to the plurality of measurement objects becomes small and the speed difference is large, the position of each measurement object can be measured correctly.

As can be seen from the previous modeling examples 2-1 - 2-4, regardless of the speed of the measurement object, you can measure the distance to the measurement object. In addition, even in the case where the distance to the plurality of measurement objects decreases and the speed difference is large, which is difficult to measure using a distance measuring device that uses a standing wave, the position of each measurement object can be correctly measured.

In the above description, a mixed wave is detected using one mixed wave detection module 3, but as shown in FIG. 14, a plurality of mixed wave detection modules 3, ..., 3 can be located at different positions x _s1 , ..., x _sN that are different from each other. A plurality of detectors 3, ..., 3 detecting the mixed wave V _C thus detect the amplitude component (amplitude a (t, x _si ) (i denotes 1, 2, N ...)) of the mixed wave by detecting the envelope with the envelope detector of each mixed wave V _c detected by each mixed wave detection module 3 (S130), each detected amplitude a (t, x _si ) is subjected to AD conversion using the AD converter (S131), and by removing the difference between any two amplitudes (for example, a (t, x _s1 ) and a (t, x _s2 ), using amplitudes, prev developed into digital signals, remove unnecessary DC components (first term of Eq. (18)), (S132), and each amplitude a (t, x _si ) without an unnecessary DC component is subjected to spectral analysis to obtain the spectrum (S133) of the distance , and after averaging each spectrum (S134) of the distance, the distance to the measurement object is calculated based on the peak of the intensity of the distance spectrum (S135) This can be obtained using, for example, means for removing the DC component, which determines the difference of any two amplitudes and eliminating m unnecessary DC component, and the distance spectrum averaging means which calculates an average value for the set of distance spectra module 5 for calculating the distance. Thus, the DC component can be removed using an analog circuit (differential amplifier, etc.), and then the signal can be subjected to AD conversion.

Therefore, in the case where the plurality of mixed wave detection modules 3 are set to constitute a signal processor, as shown in FIG. 14, unnecessary DC components can be removed. In addition, the distance spectrum obtained from each amplitude a (t, x _si ) is averaged, noise components are reduced, and the distance can be more accurately measured.

Third Embodiment

The technical solution of the third embodiment of the distance measuring device and the distance measuring method related to the claimed invention will be described below.

(Technical Solution 3)

In FIG. 15 is an illustration that explains the structure of a distance measuring device related to the claimed invention. A distance measuring device related to the claimed invention transmits a signal output from a signal source 13 in the form of a wave oscillation from a transmission unit 2 to a measurement object 6, detects a mixed wave V _C consisting of a reflected wave V _Rk reflected by the k-th object 6 the measurement, and the traveling wave V _T , in the mixed wave detection module 3, processes this mixed wave V _C using the signal processor 14, and determines the distance to the measurement object 6. The signal processor 14 comprises an amplitude component detection module 15, a single frequency detection module 16, a signal level detection module 17 and a distance calculation module 18, and a mixed wave amplitude component (a (t, x _s )) is detected using the amplitude component detection module 15, the signal (R (x (t)) of the component only at a certain frequency f _{B is} selected using the single frequency selection module 16, the level (| R (x (t)) |) of the selected signal is detected using the signal level detection module 17, and this ur the signal length, the distance to the measurement object 6 is measured using the distance calculation module 18.

The signal source 13 outputs a signal representing a carrier wave with a certain frequency, with a double frequency modulation (twice modulated signal), using a second modulating signal pre-modulated by the first modulating signal, and outputs a signal always containing two or more frequency components.

For the specific example shown in FIG. 15, the signal source 13 comprises a carrier wave signal source 13a, a second modulating signal source 13b, and a first modulating signal source 13c. A first modulating signal source 13c outputs a first modulating signal x (t) with a determined first period. The second modulating signal source 13b outputs a second modulating signal m (t), and the second modulating signal m (t) is a periodic signal with a determined second period generated by a second modulating signal source 13b, which is frequency modulated using the first modulating signal x (t ) The carrier wave signal source 13a outputs a dual modulated signal with an instantaneous frequency f ₀ + f _D · m (t) and performs frequency modulation of the carrier wave generated by the carrier wave signal source 13a with a second modulating signal m (t).

Thus, the dual-modulated signal output from the signal source 13 in accordance with the claimed invention is a carrier wave signal frequency modulated by a second modulating signal m (t), and the second modulating signal m (t) is a frequency modulated first modulating signal signal x (t). Therefore, the double-modulated signal in the claimed invention is neither a signal additionally frequency-modulated by the first modulating signal x (t), after the frequency modulation of the carrier wave signal by the second modulating signal m (t), nor a signal additionally frequency-modulated by the second modulating signal m (t), after frequency modulating the carrier wave signal with the first modulating signal x (t).

Furthermore, as another specific example of the signal source 13, as shown in FIG. 16 (a), the signal source 13 comprises a carrier wave signal source 13a (carrier wave generating means), second modulating signal generating means 13d, and second modulating signal storage means 13e. The second modulating signal storage means 13e stores the output data of the second modulating signal m (t), and the second modulating signal generating means 13d reads the data stored in the second modulating signal storage means 13e, and outputs the second modulating signal m (t). The carrier wave signal source 13a generates a carrier wave with a certain frequency, frequency modulates this carrier wave with a second modulating signal m (t) and outputs a dual-modulated signal with an instantaneous frequency f ₀ + f _D · m (t).

The second modulating signal generating means 13d is based on a microprocessor and other elements, but it only generates a second modulating signal in accordance with previously stored data; therefore, it is possible to use a processor with low functionality compared to the microprocessor used for Fourier analysis (frequency analysis) in principles 1 and 2 of measurement, and low cost is ensured.

In addition, as shown in FIG. 16 (b), the signal source 13 may comprise a dual-modulated signal generating means equipped with a microprocessor, and a dual-modulated signal storage means 13g, in which data for outputting the dual-modulated signal with an instantaneous frequency f ₀ + f _D · m ( t), and data stored in the dual modulation signal storage means 13g are read by the dual modulation signal generating means 13f to generate the dual modulated signal.

The dual modulation signal generating means 13f is also equipped with a microprocessor, but it is possible to use a processor with less functionality than the microprocessor used for Fourier analysis (frequency analysis), and a cost reduction is provided.

The transmission module 2 is a bi-directional element, such as an antenna (or electrode), designed to transmit a signal output from the signal source 13 in the form of a wave oscillation. In the case where the mixed wave detection module 3 is located between the signal source 13 and the transmission module 2, the transmission module 2 can fulfill the role of receiving the reflected wave. The transmission unit 2 outputs a wave oscillation containing frequency components output from the signal source 13, and the output wave oscillation is transmitted to the measurement object 6.

Thus, the traveling wave V _T in the claimed invention means a wave oscillation transmitted from the transmission unit 2, and a signal output from the signal source 13.

Therefore, in the case where the mixed wave of the signal from the signal source 13 and the reflected wave signal returned through the transmission unit 2 are detected by the mixed wave detection unit 3, the signal from the signal source 13 is a traveling wave V _T.

The mixed wave detection unit 3 detects a mixed wave V _C consisting of a traveling wave V _T and a reflected wave V _Rk . This mixed wave detection module 3 may be configured as an omnidirectional connector for detecting a mixed wave V _C consisting of a traveling wave V _T output by a signal source 13 and a reflected wave V _Rk returned through a transmission module 2 connected in the middle of the power feeder which connects the signal source 13 to the transmission unit 2. In addition, a receiving antenna (or electrode) for detecting a mixed wave Vc consisting of a traveling wave V _T and a reflected wave V _Rk is installed in the space between the transmission module 2 and the measurement object 6, and can be used for the mixed wave detection module 3 .

The amplitude component detection module 15 detects the amplitude component of the mixed wave V _C detected by the mixed wave detection module 3, and it includes one of an envelope detector, a quadratic detector, a synchronous detector, a quadrature detector, etc.

The single frequency selection module 16 selects one frequency component from the amplitude components of the mixed wave V _C detected by the amplitude component detection module 15 and comprises any of a quadrature detector, a bandpass filter, a matched filter, and other devices.

The signal level detection module 17 detects a signal level obtained by the single frequency selection module 16 and comprises one of an envelope detector, a quadratic detector, and other devices. In addition, the signal level detecting module 17 may comprise an AD converter, a microprocessor, and other devices, and the output signal of a single frequency detection module 16 may undergo AD conversion and the signal level may be calculated using a microprocessor.

The distance calculation module 18 calculates the distance to the measurement object 6 based on the peak of the signal level detected by the signal level detection module 17.

(Principle 3 measurements)

We now consider FIGS. 15-19, with reference to which the measurement principle of the distance measuring device and the distance measuring method, which relate to the claimed invention as follows, will be described.

When the signal source 13 performs dual frequency modulation of the carrier wave at a specific frequency using a second modulation signal that has been frequency-modulated by the first modulating signal and outputs a dual modulation signal with instantaneous frequency f ₀ + f _D · m (t), a traveling wave V _T at the time t elapsed from the beginning of the measurement, and at position x becomes a frequency-modulated undamped oscillation, which is expressed by the following Eq. (twenty):

Lv. (20)

where t is the time elapsed from the start of the measurement, c is the speed of light, A is the amplitude, θ is the phase, and any one point on the x axis is x = 0. In addition, m (t) is a step-changing signal, the instantaneous value of which increases by Δx in the first period T, as shown in the second modulating and the next Eq. (22), and is a sawtooth wave shown in FIG. 17 and the next Lv. (21):

Lv. (21)

However, [] represents the maximum integer value that does not exceed the value. m (t) is a sawtooth wave with a frequency fm, a minimum value of -1 and a maximum value of +1, as shown in FIG. 17.

Thus, the ramp recovery time shown in FIG. 17 is zero, but the sawtooth wobble may be a wobble that has a specific recovery time (i.e., a triangular wobble).

x (t) is a first modulating signal that changes the frequency f _m for m (t), and is a signal in accordance with FIG. 18 (stepped form).

Lv. (22)

Thus, when x (t) = NΔx, (N = 1, 2, ...), m (t) is frequency-modulated in such a way that the frequency f _m for m (t) corresponds to the following Eq. (23):

(η - константа)

(η is a constant) Lv. (23)

Thus, x (t) is a stepwise varying signal that increases by Δx in a particular first period, but the same principle applies even when x (t) is represented by a stepwise signal that decreases by Δx. The remainder of this section will describe a step signal in which x (t) increases by Δx.

Obviously, the first period T of the first modulating signal is longer than the ramp period (repetition time) of the second modulating signal. In addition, the ramp period of the second modulating signal is longer than the period of the carrier wave.

Denote by d _{k the} distance to the k-th measurement object 6, v _k speed, y _k and φ _{k the} size and phase of the reflection coefficient, respectively; then the reflected wave V _Rk from the measurement object 6 can be expressed as follows. (24), where k = 1, 2, ...

Lv. (24)

In this case, the mixed-wave signal V _C detected by the mixed-wave detecting unit 3 at a location where x = x _s can be expressed as follows. (25):

Lv. (25)

And the signal amplitude V _c can be expressed by the following Eq. (26):

Lv. (26)

In practice, it can be accepted that the size of the reflected wave is extremely small, y _k << 1, and the second-degree term y _k and higher can be ignored, since they are approximately equal to zero. Therefore, the equation can be approximated as the following Eq. (27):

Lv. (27)

Now, if t is made small enough, we can assume that v _k t≡0, the amplitude V _C can be approximated as the following Eq. (28), and the influence of the speed v _k can be eliminated:

Lv. (28)

In addition, when performing the approximation in the form of the following Eq. (29)

Lv. (29)

Ur (28) takes the form of the next Lv. (thirty).

Lv. (30)

where A = 1, since the constant A does not contain information in the claimed invention.

When x (t) = NΔx, the component f _{k of the} amplitude of the k-th measurement object 6 can be determined in accordance with the following Eq. (31), by differentiating the phase for a (t, x _s ):

Lv. (31)

When x (t) = NΔx is equal to d _k · x _s , the distance between the measurement object 6 and the mixed wave detection module, f _k represents the frequency f _B given by the following Eq. (32):

Lv. (32)

Therefore, if a (t, x _s ) falls into the single frequency selection module 16, such as a quadrature detector, a bandpass filter, etc., only the frequency component f _{B is} selected and the signal level is detected, it becomes possible to find out if an object is present 6 measurements at a distance x (t) = NΔx.

In the case where the quadrature detector is used as a single frequency selection module 16 to select the frequency component f _B , the output R (x (t)) with x (t) = NΔx quadrature detection can be determined using the following Eq. (33):

Lv. (33)

Thus, the quadrature detection output R (x (t)) is called the distance spectrum.

The level (intensity) of the spectrum R (x (t)) of the distance is expressed by its absolute value. That is, the intensity | R (x (t)) | may be represented by the following ur. (34):

Lv. (34)

As described above, in the distance measuring device and in the distance measuring method related to the claimed invention, a mixed wave consisting of a traveling wave and a reflected wave reflected by the measurement object 6 is detected; therefore, there is no need to separate the traveling wave and the reflected wave, and a simple structure can be obtained, and a device for measuring small distances with low cost can be obtained.

In addition, when determining the distance spectrum from a mixed wave consisting of a traveling wave having many different frequency components and its reflected wave, one can determine the distance between the measurement object and the mixed wave detection module from the distance at which the intensity of the distance spectrum takes on a peak value.

When the distance to the measurement object is measured using a standing wave, it is in principle impossible to make the observation time shorter than the time during which the standing wave is formed after switching the frequency of the traveling wave, while the peak of the distance spectrum is affected by the Doppler effect and a measurement error is generated but, in the claimed invention, in principle, there is no concept of frequency switching, and the observation time can be reduced to such a level that the Doppler effect can actually be ignored, and you can but a distance measurement.

In addition, neither a microprocessor, etc., nor any other means that can perform spectral analysis at high speed is used, and the signal processor is made in the form of an envelope detector, a quadratic detector, a synchronous detector, a quadrature detector, a bandpass filter, a matched filter and other devices, and at the same time they detect the intensity (signal level) of the distance spectrum: therefore, a signal processor that performs processing at approximately the same speed as the speed of the signal process An ora for which a microprocessor is used, etc., can be obtained at a low cost. Thus, even at low cost, a distance measuring device operating at a high signal processing speed can be obtained.

(Simulation 3)

Further, based on the above measurement principle 3, a simulation will be performed using the distance measuring device shown in FIG. 19 and 21.

With such a simulation, as shown in FIG. 19 and 21, the distance measuring device has a sine wave with a frequency f ₀ = 24.1 GHz, with a maximum frequency shift f _D = 37.5 MHz, a modulation period of the first modulating signal T = 20 μs, an instant increase in the value of the first modulating signal Δx = 0.2 m, and a constant that determines the frequency of the second modulating signal m (t) η = 1/75, and outputs a signal with an instantaneous frequency f ₀ + f _D · m (t). And the running wave V _T expressed by Ur. (20) are transmitted from transmission module 2. The mixed wave V _C (t, 0), consisting of the reflected wave V _Rk , reflected by the k-th measurement object 6, and the traveling wave V _T , are detected using the mixed wave detection module 3. Based on the detected mixed wave V _C , the signal processor 19 (24) calculates the position of the measurement object 6.

(Simulation 3-1)

In FIG. 19 is an illustration of a distance measuring device having a signal processor 19 configured with an envelope detector 20 that detects an amplitude component with a quadrature detector 21 that selects only the frequency component f _B = 1 MHz, a level detection module 22 that detects a signal level, and distance calculation unit 23.

In FIG. 20 is a graph that represents the position (x (t)) and spectrum intensity | R (x (t)) | distances when modeling is performed under conditions in which two measurement objects 6 and 6 are located at distances d ₁ = 12 m and d ₂ = 20 m, respectively, while the reflection coefficient γ ₁ = 0.01 and the phase φ ₁ = τ for a measurement object 6 located at a distance d ₁ = 12 m and a reflection coefficient γ ₂ = 0.01 and a phase φ ₂ = τ for a measurement object 6 located at a distance d ₂ = 20 m. As can be seen in FIG. 20, peaks in the intensity of the distance spectrum are obtained at points of 12 m and 20 m, respectively. This means that even if a quadrature detector, etc. used instead of a microprocessor, etc., you can correctly measure the distance.

(Simulation 3-2)

In FIG. 21 is an illustration of a distance measuring device having a signal processor 24 configured with an envelope detector for detecting an amplitude component 25, two bandpass filters 26a and 26b, an envelope detector for detecting a signal level 27, and a distance calculating module 28.

In FIG. 22 is a graph that represents the position (x (t)) and spectrum intensity | R (x (t)) | distances when modeling is performed under conditions in which two measurement objects 6 and 6 are located at distances d ₁ = 12 m and d ₂ = 20 m, respectively, the reflection coefficient γ ₁ = 0.01 and the phase φ ₁ = τ for object 6 measurement, which is located at a distance d ₁ = 12 m, the reflection coefficient γ ₂ = 0.01 and phase φ ₂ = τ for the object 6 of the measurement, which is located at a distance d ₂ = 20 m, while the band-pass filter selects the frequency f _B = 1 MHz and Q = 20.

As can be seen in FIG. 22, peaks in the size of the distance spectrum are obtained at points of 12 m and 20 m, respectively. This means that even if the bandpass filter, etc. used instead of a microprocessor, etc., you can correctly measure the distance. In the presented example, two band-pass filters are connected in series, but the number of band-pass filters should not be limited to 2, and, of course, an arbitrary number of band-pass filters can be used as needed.

Thus, in the above description, a mixed wave is detected using one mixed wave detection module 3, but a plurality of mixed wave detection modules 3, ..., 3 can be installed in different places, respectively, and based on the mixed waves detected by them, it is possible to obtain distance spectrum and the position of the measurement target 6 can be measured.

Industrial applicability

The present invention can be used as a collision avoidance system when installing a distance measuring device on moving objects, such as cars, etc., as liquid and powder level sensors, or sensors that detect a person’s presence and position in security systems.

Claims (22)

1. A distance measuring device that measures a distance to a measurement object, comprising:
a signal source that outputs a signal having a plurality of different frequency components within a certain frequency band;
a transmission module that transmits this signal in the form of a wave oscillation;
a mixed wave detection module that detects a mixed wave consisting of a traveling wave including either a wave oscillation transmitted by a transmission module or a signal output by a signal source and a reflected wave oscillation transmitted by a transmission module and reflected from the measurement object;
a frequency component analysis module that analyzes the frequency component of the mixed wave detected by the mixed wave detection module; and
distance calculation module, which determines the distance spectrum by additional processing of the analyzed data using spectral analysis and calculates the distance to the measurement object. 2. The distance measuring device according to claim 1, wherein the signal source comprises a plurality of single frequency generators, each of which generates a different component with a single frequency, and an adder that synthesizes the signals generated by the plurality of single frequency generators. 3. The distance measuring device according to claim 1, wherein the signal source comprises a single frequency generator that generates a single frequency component and a modulator that modulates a signal generated by a single frequency generator. 4. The distance measuring device according to claim 1, wherein the signal source comprises a noise source that outputs a frequency component within a certain frequency band. 5. The distance measuring device according to any one of claims 1 to 4, in which the frequency component analysis module includes an analog-to-digital (AD) converter that converts the mixed wave detected by the mixed wave detection module into a digital signal, and a signal processor, which analyzes the frequency components of the data output from the AD converter, and calculates the size of each frequency component. 6. The distance measuring device according to any one of claims 1 to 4, in which the frequency component analysis module includes a plurality of bandpass filters and a level detection module that detects an output level of the bandpass filter. 7. The distance measuring device according to any one of claims 1 to 4, in which the distance calculation module calculates the distance spectrum by subjecting the data analyzed by the frequency component analysis module to Fourier analysis. 8. The distance measuring device according to claim 5, in which the distance calculation module calculates the distance spectrum by subjecting the data analyzed by the frequency component analysis module to Fourier analysis. 9. The distance measuring device according to claim 6, in which the distance calculation module calculates the distance spectrum by subjecting the data analyzed by the frequency component analysis module to Fourier analysis. 10. A distance measuring device according to any one of claims 1 to 4, in which a plurality of mixed wave detection modules are located in different positions;
the frequency component analysis module analyzes the frequency components of each mixed wave detected by the mixed wave detection modules; and
the distance calculation module calculates the distance spectrum using the analyzed data of the frequency component of the set of mixed waves obtained. 11. The distance measuring device according to claim 5, in which
a plurality of mixed wave detection modules are located in different positions;
the frequency component analysis module analyzes the frequency components of each mixed wave detected by the mixed wave detection modules; and
the distance calculation module calculates the distance spectrum using the analyzed data of the frequency component of the set of mixed waves obtained. 12. The distance measuring device according to claim 6, in which
a plurality of mixed wave detection modules are located in different positions;
the frequency component analysis module analyzes the frequency components of each mixed wave detected by the mixed wave detection modules; and
the distance calculation module calculates the distance spectrum using the analyzed data of the frequency component of the set of mixed waves obtained. 13. The distance measuring device according to claim 7, in which
a plurality of mixed wave detection modules are located in different positions;
the frequency component analysis module analyzes the frequency components of each mixed wave detected by the mixed wave detection modules; and
the distance calculation module calculates the distance spectrum using the analyzed data of the frequency component of the set of mixed waves obtained. 14. A method of measuring distance, which measures the distance to the measurement object, comprising stages in which:
transmit by the transmission module a signal output by a signal source having a plurality of different frequency components in a certain frequency band in the form of a wave oscillation;
detecting a mixed wave, consisting of a traveling wave, including either a wave oscillation transmitted by a transmission module or a signal output by a signal source, and a reflected wave in the form of a wave oscillation transmitted by a transmission module reflected from a measurement object;
analyze the frequency component of the detected mixed wave; and determining the distance spectrum, further exposing the data analyzed using frequency component analysis to spectral analysis, and thus calculating the distance to the measurement object. 15. A distance measuring device that measures a distance to a measurement object, comprising:
a signal source that outputs a frequency-modulated signal obtained by frequency modulating a carrier wave with a specific frequency, a signal with an arbitrary frequency,
a transmission module that transmits a frequency-modulated signal in the form of a wave oscillation;
a mixed wave detection module for detecting a mixed wave consisting of a traveling wave including either a wave oscillation transmitted from a transmission module or a frequency modulated signal output from a signal source and a reflected wave in the form of a wave oscillation transmitted from a transmission module, reflected from the measurement object;
an amplitude component detection module that detects an amplitude component of a mixed wave detected by a mixed wave detection module; and
a distance calculation module that determines a distance spectrum, further exposing the amplitude component detected by the amplitude component detection module to spectral analysis, and calculates a distance to the measurement object. 16. The distance measuring device of claim 15, wherein the distance calculation module calculates a distance spectrum by subjecting the amplitude component detected by the amplitude component detection module to Fourier analysis. 17. The distance measuring device according to claim 15 or 16, wherein the plurality of mixed wave detection modules are located in different positions;
the amplitude component detection module detects the amplitude components of each mixed wave detected by the mixed wave detection modules; and
the distance calculation module calculates the distance spectrum using the amplitude component data of the plurality of mixed waves obtained. 18. A method of measuring distance, which measures the distance to the measurement object, comprising stages in which:
the transmission module transmit the signal obtained at the signal source by frequency modulating the carrier wave with a specific frequency, a signal with an arbitrary frequency, as a wave oscillation;
detecting a mixed wave, consisting of a traveling wave, including either a wave oscillation transmitted by a transmission module or a frequency-modulated signal received at a signal source, and a reflected wave in the form of a wave oscillation transmitted by a transmission module reflected from the measurement object;
detecting the amplitude component of the detected mixed wave; and
determine the distance spectrum, additionally subjecting the amplitude component to spectral analysis, and thus calculate the distance to the measurement object. 19. A distance measuring device that measures a distance to a measurement object, comprising:
a signal source that outputs a signal with a double frequency modulation, obtained as a result of double frequency modulation of the carrier wave with a certain frequency by a second modulating signal, pre-frequency-modulated by the first modulating signal;
a transmission module that transmits a dual frequency modulated signal as a wave oscillation;
a mixed wave detection module for detecting a mixed wave consisting of a traveling wave including either a wave oscillation transmitted by a transmission module or a double modulated signal output from a signal source and a reflected wave in the form of a wave oscillation transmitted from a transmission module reflected from the measurement object;
an amplitude component detection module that detects an amplitude component of a mixed wave detected by a mixed wave detection module;
a single frequency selection module that selects one specific frequency component from the amplitude components detected by the amplitude component detection module;
a signal level detecting unit that detects a signal level obtained by the single frequency selector; and
a distance calculation module that calculates a distance to a measurement object based on a signal level obtained by a signal level detection module. 20. The distance measuring device according to claim 19, in which the signal source individually generates a first modulating signal, a second modulating signal modulated by the first modulating signal, and a carrier wave; or
the signal source has means for storing a signal with double modulation, in which the signal with double modulation is stored in advance; or
the signal source has means for storing a second modulating signal, in which a second modulating signal is stored in advance, and means for generating a carrier wave that generates a carrier wave. 21. The distance measuring device according to claim 19 or 20, in which the first modulating signal is a signal that forms such a waveform that stepwise increases or decreases during a certain first period; and the second modulating signal is a signal obtained by modulating a sawtooth wave with a shorter period than the first period modulated by the first modulating signal. 22. A method of measuring the distance with which to measure the distance to the measurement object, containing stages in which:
transmitting, as a wave oscillation, the transmission module, the double-modulated signal obtained at the signal source as a result of the double frequency modulation of the carrier wave with a certain frequency by a second modulating signal pre-frequency-modulated by the first modulating signal;
detecting a mixed wave consisting of a traveling wave including either a wave oscillation transmitted by a transmission module or a dual frequency modulated signal received at a signal source and a reflected wave in the form of a wave oscillation transmitted by a transmission module reflected from a measurement object;
detecting the amplitude component of the detected mixed wave;
selecting one specific frequency component from the amplitude components;
detecting a signal level of a selected frequency component; and
calculate the distance to the measurement object by signal level.

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